Recently, in a semiconductor manufacturing process, further improvement in a microfabrication technique has been required along with an increase in element integration density and performance. In the semiconductor manufacturing process, an etching technique is one of the important microfabrication techniques. Recently, among the etching techniques, a plasma etching technique capable of microfabrication on a large area with high efficiency has been mainly used.
This plasma etching technique is a dry etching technique. In this technique, a mask pattern is formed on a solid material as a workpiece through a resist, and this solid material is supported in a vacuum. In this state, by introducing reactive gas into this vacuum and applying a high-frequency electric field to the reactive gas, accelerated electrons collide against gas molecules to be in a plasma state, radicals (free radicals) produced from the plasma and ions are caused to react with the solid material so as to be removed as a reaction product. As a result, a fine pattern is formed on the solid material.
On the other hand, in a plasma CVD method which is a thin film forming technique, a compound, which is obtained by plasma causing raw material gases to combine with each other, is deposited on a substrate. This method is a film forming method including: applying a high-frequency electric field to gases containing raw material molecules to discharge plasma; decomposing the raw material molecules with electrons accelerated by the plasma discharge to obtain a compound; and depositing the obtained compound on a substrate. A reaction, which does not occur only with thermal excitation at a low temperature, may occur in plasma because gases in the system collide against each other and are activated into radicals. In a semiconductor manufacturing device using plasma such as a plasma etching device or a plasma CVD device, in the related art, an electrostatic chuck device is used as a device which simply attaches and fixes a wafer to a sample stage and maintains the wafer at a desired temperature.
However, in a plasma etching device of the related art, when a wafer fixed to an electrostatic chuck device is irradiated with plasma, the surface temperature of the wafer increases. Therefore, in order to suppress an increase in the surface temperature, the wafer is cooled from the bottom side by circulating a coolant such as water in a base portion for adjusting the temperature of the electrostatic chuck device. However, at this time, an in-plane temperature distribution is generated in the wafer. For example, the temperature at the center of the wafer is high, and the temperature at a peripheral portion thereof is low.
In addition, the in-plane temperature distribution of the wafer varies depending on, for example, a difference in the structure or type of a plasma etching device.
Therefore, a heater function-equipped electrostatic chuck device is proposed in which a heater member is attached between an electrostatic chuck portion and the base portion for temperature adjustment (for example, refer to Patent Literature No. 1).
In this heater function-equipped electrostatic chuck device, a local temperature distribution can be generated in a wafer. Therefore, by setting an in-plane temperature distribution of a wafer according to a film deposition rate or a plasma etching rate, local film formation such as pattern formation on a wafer or local plasma etching can be efficiently performed.
Examples of a method of attaching a heater to an electrostatic chuck device include: a method of providing a heater in a ceramic electrostatic chuck; a method of attaching a heater by applying a heater material to a back side of an adsorption surface of an electrostatic chuck, that is, to aback surface of a ceramic plate-shaped body through screen printing in a predetermined pattern and thermally curing the heater material; and a method of attaching a heater by adhering a metal foil or a sheet-shaped conductive material to the back surface of the ceramic plate-shaped body.
Subsequently, the electrostatic chuck portion, in which a heater is provided or to which a heater is attached, and the base portion for temperature adjustment are adhered to each other and integrated through an organic adhesive, thereby obtaining a heater function-equipped electrostatic chuck device.